1. Field of the Invention
The present invention relates generally to an electric motorcycle, and more particularly to a driving device and an electric motorcycle driving system using the driving device.
2. Description of Related Art
To meet the demands of environment protection and energy saving, electric motorcycles are becoming more and more popular than the traditional gasoline motorcycles. The energy used by electric motorcycles is electric power, which features no waste gas discharge and no noise pollution comparing to the engine-driven gasoline motorcycles. However, the speed of electric motorcycles will be limited by the rotational speed and power of the motor itself. Because the motor outputs a low torque under a low speed, and a high torque under a high speed, it is unable to meet the requirement for low speed and high torque. Under a high speed, the motor consumes considerable electric power. Also, as it has no speed change function, the performance of electric motorcycles still falls behind the gasoline motorcycles using the continuously variable transmission (CVT). Secondly, as the electric motorcycles have limited inner space to house the motor and battery, there is limitation for motor installation position and driving mode, which further affects the performance of electric motorcycles.
In recent years, there are some kinds of electric motorcycles provided with continuously variable transmission (CVT) or automatic speed change systems to enhance the performance. Although the electric motorcycles with continuously variable transmission (CVT) or automatic speed change systems offer better performance than the traditional electric motorcycles, they have bigger sizes and their rotational speed is still limited by the power design of the motor.